Child Theme keeps breaking my website

Hi,

So this is so incredibly frustrating. Everyone praises child themes and how great they are. But whenever I try to follow the simple instructions for setting mine up, it breaks my site.

I took a screen cap of the problem:
http://screencast.com/t/ew4Bp1NYWFw

Basically, just as you can see from that link, whenever I activate the child theme it messes up all of the formatting of my site. I’m writing the rules just as it says in all of the tutorials. And it’s not the styling that’s causing it because I can delete the style rules and it still doesn’t work whenever I activate the child theme.

Been trying to figure this out forever, if anyone can offer help it would be mucho appreciated.

Gracias.